Over the years, numerous consumer products have been manufactured and marketed for cleansing teeth of tartar and plaque. The products have taken the form of toothpastes, powders, gels, liquid rinses, chewing gum, dental floss, or other suitable delivery systems. The formation of tartar and plaque on clean teeth is a complex process, which begins with bacteria in the mouth.
This process begins within a few minutes after the teeth have been professionally cleaned by a dentist or hygienist. The first bacteria start attaching to the pellicle on the tooth surface, tongue, and gums. This first layer of bacteria allows other bacteria to attach. These bacteria then multiply by cell division to form a complex structure called a biofilm. After two to three hours, the biofilm thickness increases to the point that a visible film of bacteria can be seen by the naked eye.
This visible film of bacteria is called plaque and, over time, the bacteria in protected areas of the mouth grow into thick structures known as mature plaque. If this plaque is not disturbed by flossing or brushing, it begins to mineralize as calcium and phosphate ions from saliva start to deposit within the bacterial colony and harden to form crystalline tartar. Most toothpaste achieves their cleaning action from abrasives which can comprise about 50% of the typical toothpaste. These insoluble abrasives help remove plaque from accessible portions of the teeth. Brushing, however, will not remove tartar. Traditional toothpaste and other traditional mouth rinses can help prevent tartar buildup, but they cannot remove it once it has formed. Until now, only a dental hygienist or dentist could remove tartar by physically scraping it from the tooth surface with specialized metal instruments. The physical process by which a dentist or hygienist scrapes tartar from teeth is called “scaling.” During a scaling, the dentist or hygienist uses special stainless steel instruments to remove tartar from the teeth both above and below the gum line.
Dental plaque is a biofilm (usually a pale yellow to whitish color) that builds up on the surface of teeth. If not removed regularly, it can lead to dental cavities (caries) or periodontal problems (such as gingivitis). The microorganisms that form the biofilm are almost entirely bacteria (mainly Streptococcus and anaerobes), with the composition varying by location in the mouth. The microorganisms present in dental plaque are all naturally present in the oral cavity, and are normally harmless. However, failure to remove plaque allows it to build up in a thick layer and leads to increased bacterial growth.
Dental plaque is a precursor of tartar, which is also known as calculus. Both terms, “tartar” and “calculus,” are used interchangeably to refer to mineralized dental plaque, where the mineral may be calcium. This build-up of hardened (mineralized) plaque on the teeth is formed by the presence of saliva, debris, glucans, and minerals. Typically tartar is primarily comprised of four or more calcium phosphate mineral salts, including octacalcium phosphate, hydroxyapatite, whitlockite, and brushite. These salts are deposited within and between remnants of the biofilm and plaque bacterial colony. Mature tartar consists of an inorganic portion which is largely calcium phosphate arranged in a hydroxyapatite crystal lattice structure similar to bone, enamel, and dentine. An organic portion is also present and consists of desquamated epithelial cells, leukocytes, glucans, salivary sediment, food debris, and various types of microorganisms. The rough surface of mature tartar provides an ideal medium for bacterial growth, threatening the health of the gums and absorbing unaesthetic stains far more easily than natural teeth.
The longer that tartar, plaque, and the bacteria they protect remain on the teeth, the more damage they can cause. Initially, accumulation of tartar, plaque, and bacteria may simply irritate and inflame the gingiva, the part of the gum around the base of the teeth. This is called gingivitis, the mildest form of periodontal disease. Ongoing inflammation eventually causes pockets to develop between the gums and teeth that fill with plaque, tartar and bacteria. Bacteria can deposit endotoxins—a byproduct of their own metabolism—which are responsible for much of the inflammation that can be caused around teeth. In time, these pockets in the gums become deeper and, as more bacteria accumulate, eventually advance under the gum tissue. These deep infections can cause a loss of tissue and bone. If too much bone or tissue is destroyed, one or more teeth may be lost.
There are two basic forms of tartar. Supragingival (outside the gums) tartar is the visible deposit that forms on the top of the teeth. Subgingival (inside the gums) tartar forms in pockets between teeth and gums. Subgingival tartar is more harmful because it promotes faster growth of bacteria. Buildup of tartar often causes swelling, bleeding and weakening of gums, and can lead to gum recession and tooth loss. Tartar can even extend into pockets created between the teeth and gums. The anaerobic bacteria found in pockets around teeth may be linked to cardiovascular disease and pre-term low birth weight babies. These pockets are difficult to reach by tooth brushing, and are not affected by standard mouthwashes.
Regularly scheduled teeth cleanings every six months with a dentist or dental hygienist where scaling of the teeth is performed can be effective for the removal of accumulated tartar and plaque. Scheduling regular professional dental cleanings, however, can be difficult in areas where access to a dental professional is limited or the demands of busy schedules require the cancellation or postponement of professional teeth cleanings. Moreover, certain individuals can be genetically predisposed to the rapid formation and accumulation of tartar, which requires more frequent (usually every three months) professional dental cleanings than the typical six-month interval.
Although the mechanical dental scaling procedure may be effective in tartar removal, in addition to being very time-consuming, this procedure has several disadvantages. One disadvantage of dental scaling is that the process can destroy dental cementum, which is a tooth formation critical to gum/tooth attachment. Another disadvantage of dental scaling is that the treatment may remove healthy gum tissue, which cannot regenerate. Still another disadvantage is that the procedure is painful and often causes bleeding and swelling of the gums when tartar accumulation is substantial. An economic disadvantage is that dental scaling is almost exclusively done by a dental professional and is relatively expensive.
A variety of chemical and biological agents have been suggested to retard tartar formation. Pyrophosphate salts and other chemical agents are known to have the ability to retard tartar formation. Current anti-tartar oral formulations designed for preventing the accumulation of tartar on the teeth often incorporate as an active ingredient sodium pyrophosphate, tetrasodium pyrophosphate, or other types of pyrophosphate compounds to prevent calcium phosphate salts from depositing on the enamel of teeth. One example can be found in U.S. Pat. No. 8,303,938. Compounds containing pyrophosphate, however, can result in tooth sensitivity and mouth lesions in some individuals. Moreover, none of the anti-tartar oral formulations containing pyrophosphate compounds are very effective at actively removing tartar from teeth once the calcium phosphate salts have bonded with tooth enamel.
Other chemicals reportedly have been used to inhibit the formation of plaque and calculus on teeth. For example, in U.S. Pat. No. 4,610,871 describes the use of monoalkyl or dialkyl ethers of dianhydrohexitols to inhibit the formation of plaque and calculus on teeth is described. U.S. Pat. No. 4,178,363 describes the use of n-undecylenic acid or a calcium or zinc salt thereof for reducing dental plaque and infections of the teeth and gums. U.S. Pat. No. 4,119,711 describes spiro 1-(hydroxyalkyl) piperidino derivatives, which have efficacy in reducing the formation of plaque. Additionally, U.S. Pat. No. 3,887,712 discloses that alexidine dihydrofluoride is useful in the treatment of dental plaque, calculus, gingivitis, and related periodontal diseases. U.S. Pat. No. 4,160,821 discloses that a glycerin solution of zinc chloride or other acceptable zinc salts provides effective therapy for gingivitis when applied to the gingival and teeth. U.S. Pat. No. 4,060,600 teaches a method of treating teeth in dentistry, for the prevention of calculus, removal of caries, and dissolution of plaque, comprising applying an aqueous solution containing a hypochlorite of an alkali and/or alkaline earth metal, and an amino compound capable of forming water-soluble non-mucous irritating N-chloro and/or N-dichloro derivatives thereof to the teeth. All of these chemical and biological agents have some disadvantages, such as limited effectiveness, discoloration of teeth or tongue, desquamation and soreness of oral mucosa, objectionable taste, toxicity, and may also cause an imbalance of the oral flora.
Dimethyl isosorbide (DMI) is a hydrophilic and highly polar compound. DMI is a non-toxic solvent and carrier that is considered to be neither a primary irritant to human skin nor a skin sensitizer. DMI also provides a safe and effective delivery enhancement mechanism for active ingredients in skin care products, such as sunless tanners, facial and eye-zone treatments, skin serums, anti-acne formulations and make-up removers.
DMI was studied in the 1980's for use in dentifrices and oral care formulations for inhibiting the formation of plaque and calculus in the mouth (Lynch U.S. Pat. Nos. 4,585,649; 4,610,871; and 4,627,974). Lynch demonstrated that DMI has antibacterial properties against Streptococcus mutans and that DMI is a weak antibacterial at high concentrations. Lynch also observed that collected dental tartar was slowly dissolved by DMI in an occasionally stirred beaker over a 24 hour period at 100% and 50% aqueous concentrations. Lynch, however, did not provide any findings concerning whether DMI was capable of in vivo removal of tartar from teeth and gums.
DMI was considered for use as an antibacterial for oral applications in the 1980's and was heavily marketed into the personal care and oral health industries in the Americas, Europe, Australia, and Japan. DMI has been found to be an excellent delivery enhancer, which can place active ingredients where they are needed most on the skin. This functionality of DMI has been used in sunless tanners, facial and eye-zone treatments, skin serums, anti-acne formulations and make-up removers. In oral hygiene applications, DMI has found little if any use as a delivery enhancer in oral applications.
Originally, DMI was thought to have use as an antibacterial in oral applications, but its antibacterial functionality is weak and more effective anti-bacterials such as Triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol), chlorohexidine gluconate, and zinc and other metal salts are used as antibacterials in oral applications. As described above, DMI has shown some utility in dissolving tartar in vitro over a period of 24 hour, sustained exposure in the Lynch U.S. Pat. Nos. 4,627,974 and 4,610,871, but was not effective at removing tartar from subjects' teeth in vivo. DMI is also relatively expensive at nearly $100.00 per kilogram for personal care products. Where it is found in products, it is usually present in the 0.1% (w) to 2% (w) levels. Thus, DMI is only considered for high value delivery enhancement application in the personal care industry. Moreover, industry had largely abandoned research and the use of DMI in the oral hygiene setting as an unsuccessful, limited spectrum, oral antiseptic that was cost-prohibitive. There currently are no known commercial toothpastes or mouthwashes containing DMI for sale on the dental care market.
Chlorine dioxide (ClO2) is a highly soluble gas that does not hydrolyze when combined with water. Instead, it remains dissolved as a gas in solution. Chlorine dioxide has been used as a powerful and safe disinfectant and biocide for almost 200 years, including for many industrial applications. More recently, chlorine dioxide has been used for removing bacteria and biofilm from cooling towers and potable water lines. When applied correctly, it has been shown to control a broad range of biofilms and bacteria.
Chlorine dioxide is strongly oxidizing and can be explosive in concentrations exceeding 10% (v/v). Because “active” chlorine dioxide, ClO2, is highly reactive with other chemicals, it is often converted to a stabilized form for transporting and mixing, as described in McNicholas U.S. Pat. No. 3,271,242. Active chlorine dioxide can also be prepared at the time of use by combining chlorite source (for example sodium chlorite, potassium chlorite, or calcium chlorite) with a weak food or cosmetic grade acid (for example, citric acid, lactic acid, sodium bisulfate, or disodium phosphate), which produces chlorous acid as an intermediate, which in turn forms active chlorine dioxide. Stabilized chlorine dioxide and a two-part product, which uses sodium chlorite and weak organic acids such as citric acid have been available for many years, and have been largely used for industrial, bleaching, oxidizing and surface cleaning applications.
Chlorine dioxide has normally been used in industrial applications such as the whitening of paper pulp, and other bleaching and oxidizing activities. More recently chlorine dioxide has been found to be effective in disinfecting hard surfaces such as countertops and walls and is promoted to disinfect animal drinking water as well as other similar applications. Chlorine dioxide has a noticeable odor similar to chlorine, which is still noticeable at aqueous concentrations as low as 10 ppm. People working with high concentrations of chlorine dioxide must normally wear personal protective equipment to prevent possible skin and eye contact. Chlorine dioxide reacts with many organic compounds and under many conditions “active” chlorine dioxide has poor shelf stability. These facts either singularly or in combination normally dissuade most development personnel from considering chlorine dioxide as an additive to personal care products let alone oral care applications.
Recent advances have made chlorine dioxide available for use in a few niche oral care mouthwashes and toothpastes, which strive to control bad breath by destroying the bacteria that causes bad breath. Examples of these commercial oral uses are CloSYS® oral rinse and toothpaste, DioxiRinse™ mouthwash, DioxiBrite™ toothpaste and ultraDEX® oral rinse to name a few. The bacteria reduction asserted to occur through use of these products is also said to reduce plaque. These products also claim additional teeth whitening effects due to the oxidation of dental stains by chlorine dioxide. Chlorine dioxide containing toothpastes and mouth rinses may marginally lessen the rate of tartar build up by destroying bacteria and plaque. But neither chlorine dioxide by itself nor any commercially available formulations are effective in removing tartar from teeth. Instead, they have been found to be ineffective in removing tartar.
Accordingly, there has been a long-felt but unmet need for a product or method that allowed an individual to actively remove accumulated tartar and plaque from one's teeth between professional cleanings.